package com.hmdp.service.impl;

import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import cn.hutool.json.JSONObject;
import cn.hutool.json.JSONUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.entity.Shop;
import com.hmdp.mapper.ShopMapper;
import com.hmdp.service.IShopService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.CacheClient;
import com.hmdp.utils.RedisConstants;
import com.hmdp.utils.RedisDate;
import com.hmdp.utils.SystemConstants;
import org.springframework.data.geo.Distance;
import org.springframework.data.geo.GeoResult;
import org.springframework.data.geo.GeoResults;
import org.springframework.data.redis.connection.RedisGeoCommands;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.domain.geo.GeoReference;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.Resource;

import java.time.LocalDateTime;
import java.util.*;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

import static com.hmdp.utils.RedisConstants.*;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class ShopServiceImpl extends ServiceImpl<ShopMapper, Shop> implements IShopService {

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private CacheClient cacheClient;

    @Override
    public Result queryById(Long id) {
        //缓存穿透，返回redis空值
        //Shop shop = queryWithPassThrough(id);
        //Shop shop = cacheClient.queryWithPassThrough(CACHE_SHOP_KEY,id,Shop.class,id2 ->getById(id),CACHE_SHOP_TTL,TimeUnit.MINUTES);

        // 用互斥锁解决缓存击穿
        //Shop shop = queryWithMutex(id);

        //用逻辑过期来解决缓存击穿问题
        // Shop shop = queryWithLogicalExpire(id);
        Shop shop = cacheClient.queryWithLogicalExpire(CACHE_SHOP_KEY, id, Shop.class, id2 -> getById(id), CACHE_SHOP_TTL, TimeUnit.MINUTES);
        if (shop == null) {
            return Result.fail("店铺不存在");
        }
        return Result.ok(shop);
    }

    //private static final ExecutorService CACHE_REBUIDE_EXECUTOR = Executors.newFixedThreadPool(10);

/*    *//**
     * 逻辑过期
     * @param id
     * @return
     *//*
    public Shop queryWithLogicalExpire(Long id) {
        //1 从redis查询商铺缓存
        String shopJson = stringRedisTemplate.opsForValue().get(CACHE_SHOP_KEY+id);
        //2 判断是否存在
        if (StrUtil.isBlank(shopJson)) {
            //3 存在，直接返回
            return null;//将json格式转成shop对象
        }
        //4 命中，需要先把json反序列化为对象
        RedisDate redisDate = JSONUtil.toBean(shopJson, RedisDate.class);
        //Shop shop = (Shop) redisDate.getData();
        Shop shop = JSONUtil.toBean((JSONObject) redisDate.getData(), Shop.class);
        LocalDateTime expireTime = redisDate.getExpireTime();
        //5 判断是否过期
        if (expireTime.isAfter(LocalDateTime.now())) {
            //5.1 未过期，直接返回店铺信息
            return shop;
        }
        //5.2 过期，需要缓存重建
        //6 缓存重建
        //6.1 获取互斥锁
        String lockKey =LOCK_SHOP_KEY + id;
        //6.2 判断是否获取锁成功
        if (tryLock(lockKey)) {
            //6.3 成功，开启独立线程，实现缓存重建
            CACHE_REBUIDE_EXECUTOR.submit(()->{
                try {
                    this.saveShop2Redis(id,20L);
                } catch (Exception e) {
                    throw new RuntimeException(e);
                } finally {
                    //释放锁
                    unLock(lockKey);
                }
            });
        }
        //6.4 返回过期的商铺信息
        return shop;
    }

    *//**
     * 实现互斥锁
     * @param id
     * @return
     *//*
    public Shop queryWithMutex(Long id) {
        //1 从redis查询商铺缓存
        String shopJson = stringRedisTemplate.opsForValue().get(CACHE_SHOP_KEY+id);
        //2 判断是否存在
        if (StrUtil.isNotBlank(shopJson)) {
            //3 存在，直接返回
            return JSONUtil.toBean(shopJson, Shop.class);//将json格式转成shop对象
        }
        //判断命中的是否是空值
        if ("".equals(shopJson)) {
            return null;
        }

        //4 实现缓存重建
        //4.1 查数据库之前，先获取互斥锁
        String lockKey =LOCK_SHOP_KEY + id;
        Shop shop = null;
        try {
            boolean isLock = tryLock(lockKey);
            //4.2 判断是否获取成功
            while (!isLock) {
                //4.3 失败，则休眠并重试
                Thread.sleep(50);
                queryWithMutex(id);
            }
            //4.4 成功，根据id查询数据库
            shop = getById(id);
            //模拟重建的延时
            Thread.sleep(200);
            if(shop == null) {
                // 将空值写入redis
                stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY+id,"",CACHE_NULL_TTL, TimeUnit.MINUTES);
                //5 不存在，返回错误
                return null;
            }
            //6 存在，写入redis
            stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY+id,JSONUtil.toJsonStr(shop),CACHE_SHOP_TTL, TimeUnit.MINUTES);//将shop对象转成json格式
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        } finally {
            // 释放互斥锁
            unLock(lockKey);
        }
        //7 返回
        return shop;
    }

    *//**
     * 拿锁
     * @param key
     * @return
     *//*
    private boolean tryLock(String key){
        Boolean flag = stringRedisTemplate.opsForValue().setIfAbsent(key, "1", LOCK_SHOP_TTL, TimeUnit.SECONDS);
        return BooleanUtil.isTrue(flag) ;
    }

    *//**
     * 释放锁
     * @param
     *//*
    private void unLock(String key){
        stringRedisTemplate.delete(key);
    }*/

    @Override
    @Transactional
    public Object update(Shop shop) {
        Long id = shop.getId();
        if (id== null) {
            return Result.fail("店铺id不能为空");
        }
        //1 更新数据库
        updateById(shop);
        //2 删除缓存
        stringRedisTemplate.delete(CACHE_SHOP_KEY+id);
        return Result.ok();
    }

    @Override
    public Result queryShopByType(Integer typeId, Integer current, Double x, Double y) {
        // 是否根据坐标查询
        if(x == null || y == null){
            // 根据类型分页查询
        Page<Shop> page = query()
                .eq("type_id", typeId)
                .page(new Page<>(current, SystemConstants.DEFAULT_PAGE_SIZE));
        // 返回数据
        return Result.ok(page.getRecords());
        }
        // 2.计算分页参数
        int from = (current - 1) * SystemConstants.DEFAULT_PAGE_SIZE;
        int end = current * SystemConstants.DEFAULT_PAGE_SIZE;

        // 查询redis，按照距离排序、分页
        String key = SHOP_GEO_KEY + typeId;
        GeoResults<RedisGeoCommands.GeoLocation<String>> results = stringRedisTemplate.opsForGeo()
                .search(key, GeoReference.fromCoordinate(x, y)
                        , new Distance(5000)
                        , RedisGeoCommands.GeoSearchCommandArgs.newGeoSearchArgs().includeDistance().limit(end)
                );
        if (results == null) {
            return Result.ok(Collections.emptyList());
        }
        List<GeoResult<RedisGeoCommands.GeoLocation<String>>> list = results.getContent();
        if (list.size() <= from) {
            // 没有下一页了，结束
            return Result.ok(Collections.emptyList());
        }
        // 4.1.截取 from ~ end的部分
        List<Long> ids = new ArrayList<>(list.size());
        Map<String, Distance> distanceMap = new HashMap<>(list.size());

        list.stream().skip(from).forEach(result ->{
            // 4.2.获取店铺id
            String shopIdStr = result.getContent().getName();
            ids.add(Long.valueOf(shopIdStr));
            // 4.3.获取距离
            Distance distance = result.getDistance();
            distanceMap.put(shopIdStr, distance);
        });
        // 5.根据id查询Shop
        String idStr = StrUtil.join(",", ids);
        List<Shop> shops = query().in("id", ids).last("ORDER BY FIELD(id," + idStr + ")").list();
        for (Shop shop : shops) {
            shop.setDistance(distanceMap.get(shop.getId().toString()).getValue());
        }
        return Result.ok(shops);
    }

    /**
     * 查数据库，设置过期时间，逻辑上的
     * @param id
     * @param time
     */
    public void saveShop2Redis(Long id,Long time) {
        //1 查询店铺数据
        Shop shop = getById(id);
        //2 封装逻辑过期时间
        RedisDate redisDate = new RedisDate();
        redisDate.setData(shop);
        redisDate.setExpireTime(LocalDateTime.now().plusSeconds(time));
        //3 写入redis,永久有效这个ExpireTime
        stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY+id,JSONUtil.toJsonStr(redisDate));
    }

/*    *//**
     * 解决缓存穿透(没有工具类)
     * @param id
     * @return
     *//*
    public Shop queryWithPassThrough(Long id) {
        //1 从redis查询商铺缓存
        String shopJson = stringRedisTemplate.opsForValue().get(CACHE_SHOP_KEY+id);
        //2 判断是否存在
        if (StrUtil.isNotBlank(shopJson)) {
            //3 存在，直接返回
            return JSONUtil.toBean(shopJson, Shop.class);//将json格式转成shop对象
        }
        //判断命中的是否是空值
        if ("".equals(shopJson)) {
            return null;
        }
        //4 不存在，根据id查询数据库
        Shop shop = getById(id);
        if(shop == null) {
            // 将空值写入redis
            stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY+id,"",CACHE_NULL_TTL, TimeUnit.MINUTES);
            //5 不存在，返回错误
            return null;
        }
        //6 存在，写入redis
        stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY+id,JSONUtil.toJsonStr(shop),CACHE_SHOP_TTL, TimeUnit.MINUTES);//将shop对象转成json格式
        //7 返回
        return shop;
    }*/
}
